. >> reporter: joe biden and paul ryan don't debate until next week. so they're on the trail representing their campaigns this tuesday, biden in north carolina and ryan in iowa of jennifer davis, fox news. >> you can watch that first presidential debate on fox 5 at 9:00 tomorrow night live from denver. >>> a scare in the air for american airlines. passengers had a row of seats come loose in midflight. now the airline figured out why. will thomas is everywhere at 11:00. >> american airlines is responding. it says the clasps that hold the seats in place were installed improperly on several planes. so the seats came loose while the planes were up in the air. no one was hurt, but some flights had to be diverted for safety reasons. american airlines is stuck in contract negotiations with a labor union, but officials say the problem is a mechanical issue and not related to the labor problems. >> the results are in. there is no trace of jimmy hoffa's remains in a sample dug up from a driveway near detroit. the teamsters boss vanished 40 years ago. a tipster p